Posted
by
timothy
on Thursday January 21, 2010 @04:56PM
from the feed-it-pooh-pooh-undies dept.

Julie188 writes "Researchers from the University of Virginia have found that current algae biofuel production methods consume more energy, have higher greenhouse gas emissions and use more water than other biofuel sources, such as switchgrass, canola and corn. The researchers suggest these problems can be overcome by situating algae production ponds behind wastewater treatment facilities to capture phosphorous and nitrogen — essential algae nutrients that otherwise need to come from petroleum."

When you see that growing corn to produce ethonal requires petroleum, do you assume that they dump petroleum on the corn fields? No, you assume that petroleum is required to run the tractor, run the truck that delivers the fertilizer, or heat the reactor vessle that makes the fertilizer.

Assume this means that petroleum must be consumed in the delivery mechanism for phosphorus and nitrogen. Perhaps because they need to drive a truck to deliver it, or maybe the chemical reaction to fix it requires petroleum or burning petroleum, or whatever. Obviously it doesn't mean that these elements are extracted directly from petroleum.

The company that I worked for commissioned a few studies on algae based biofuels. It turns out that the most efficient way of handling the material was to collect the algae in cakes and burn it in a reactor to make synthesis gas. Synthesis gas is a mixture of CO and Hydrogen. If you add steam, you could then perform a shift reaction to get methane or methanol. The main value of the process was not in producing fuel, or generating electricity. The main thing you could use it for was as a chemical feedstock. Methanol is a good starting point for many plastics.

Nitrogen fertilizer (ammonia) is made from natural gas through the Haber Bosch process. Phosphorus is produced in a relatively small number of huge mines and shipped around the world by a supply chain powered by oil

Population size makes a big difference. It wasn't until around 1800 that the population of the Earth was close to 1 billion. We're now adding that many people in less than 20 years but we are NOT adding enough land to take care of that increase.

On a side note, Oregon State University in Corvallis, OR, and Reed College, in Portland, OR, both have reactors on campus. the Reed college one, you don't have to be in an engineering program to use it!

No. The Haber ammonia synthesis process requires a source of hydrogen to run. It is just that currently the cheapest way to generate hydrogen is steam reforming of natural gas. Natural gas, not petroleum. Hydrogen can just as well be generated from electrolysis (if you have cheap electricity), sulfur-iodine cycle (if you have an available source of heat), or whatever from water.

I notice a few people commenting on using fresh water. Well according to CSIRO (Australia) you can happily use salt water [biofuelsdigest.com] There is even a prototype plant that has been commissioned [abc.net.au] to look at making this more cost effective.

This sounds like the University of Virgina is just regurgitating information published by Michael Briggs of the University of New Hampshire.
http://www.energybulletin.net/node/2364 [energybulletin.net]
This isn't really a new idea nor a new recommendation. It is sad that it is at least 6 years old and it is being treated as new information though.

To make fertilizer, you want fixed N (that is, N that is connected to carbon). Doing that is a big part of the energy cost in the fertilizer.(this doesn't mean you can't come up with an algae good at fixing N; but there's plenty of N around anyway, N2 is most of our atmosphere. Such would be a good starting point for using algae to make fertilizer. My point is what we're really trying to get out of the algae is energy, which making fertilizer also requires).

Natural gas is often processed with petroleum as they are often in the same fields. Processing natural gas into hydrogen (steam forming) requires energy. The Haber Process requires energy. Most often electricity is required to run the machinery. The vast amount of electricity comes from fossils fuels.

Neither the hydrogen nor the electricity come from petroleum. Most fossil fuels and hydrogen sources are not petroleum. These distinctions matter in some areas like a consideration of the effects of radical oil supply drops (commonly called "peak oil").

That's the problem with simplistic cost analyses; they ignore the fact that if a lot of something is produced, it tends to get cheaper. On the other hand the demand for algae for biodiesel would tend to drive costs up.

The secret is that competition tends to drive costs down to "normal profit" levels. If you could sell algae cheap enough to replace diesel, sooner or later somebody will undercut the algae as feed prices, unless one company has the exclusive rights to the magic process that makes cheap algae possible.

That's not quite true. The vast majority of the world's livestock farms aren't on land that's suitable for arable farming. Furthermore, without the livestock farms you are wholly dependant on petrochemical-derived fertilisers and human waste for farming - but it turns out that to make human waste from sewage plants safe to use as fertiliser, you need lots of petrochemicals. Oops.

Good question. Even industrial rotary drum filters:http://en.wikipedia.org/wiki/Rotary_vacuum-drum_filter [wikipedia.org]get clogged easily by the microscopic algae.Also "the container" to be economical must be these so-called raceway ponds and there is no "tilting" somethingthe size of a farm.

Again if you read up, algae has been a proposed sourceof fuel for a very long time. Unfortunately the devil is in theengineering challenges (and the biology -- this is a kindof agriculture but with major disadvantages in that the "weeds"are microscopic). It seems like every problem conspires tomake it more expensive.

This is actually not true. In most cases the algae are harvested (i.e. killed) to get the biodiesel out of them, because they are unable to secrete them. Even in cases where they are secreting them, there are other problems. Sun light exposure requirement means large ponds or expensive transparent reactor technologies maximizing surface area. There are 1-2 companies which are not using sunlight but using dark reactors and giving the algae food (glucose or other sugars and nutrients). That is, they use the algae for their oil producing property. So overall, it is a lot complicated than the simplistic pitches that go like 'they capture sunlight and CO2 and produce diesel'.

Feedlot cattle are mostly an eastern thing. Out here cattle are grass-fed on land unsuitable for growing corn and soy. While it is true that the two largest beef-cattle states (Nebraska and Texas) raise a majority of their cattle on lots, they are the exception. Head north or west and almost 100% of the cattle is grazed.

In 2003 only ~40% of US beef cattle was grain-fed, and of that most were only grain fed the later days of their lives.